The present invention relates to new imidazolyl guanidine derivatives which by virtue of their agonistic action on histamine-H.sub.2 receptors and in part also their additional H.sub.1 -antagonistic receptor activity may be used in cardiac diseases, certain forms of hypertension and diseases of arterial occlusion. Histamine used as specific stimulator of the H.sub.2 receptors produces adverse, in some cases lethal effects in the form of bronchospasm and anaphylactic shock due to its H.sub.1 -agonistic action and therefore cannot be used therapeutically for the treatment of the above-mentioned disorders.
It is therefore an object of the present invention to compensate for the disadvantageous effects of histamine and provide better and more selectively acting H.sub.2 -agonists in which the harmful side effects due to an H.sub.1 -agonistic active component may be avoided by an additional H.sub.1 -antagonistic activity profile.
This problem is solved by the present invention.